Testifying on the fifth day of the trial at the Pretoria High Court, Pieter Baba, who was on guard duty the night Pistorius killed 29-year-old Reeva Steenkamp, said he received a call from the athlete at 3:21 a.m., around five minutes after Steenkamp was shot.

Pistorius was too upset to say anything on the call, Baba said, speaking in Afrikaans through an interpreter.

However, when Baba - concerned that something was wrong - called him back a few minutes later, Pistorius told him: "Security, everything is fine." Baba delivered the quote in English.

The dramatic testimony from one of the first people on the scene capped a week of hearings in which several witnesses described hearing a woman's shouts and screams before a volley of shots in the early hours of Valentine's Day last year.

Steenkamp died after being hit by three of four rounds fired by Pistorius from a 9 mm pistol through the door of a toilet cubicle in an upstairs bathroom in his luxury home in a Pretoria gated community. The shooting stunned South Africa and millions of Pistorius supporters around the world.

The 27-year-old - one of the most recognized men in world athletics - denies murder, saying it was a tragic accident and that he mistook her for an intruder. If found guilty, he is likely to spend at least 25 years behind bars.

"SHOOT A ROBOT"

As well as the murder charge, Pistorius is being tried for three firearms offences, part of prosecution attempts to portray him as a gun-obsessed hot-head.

Earlier on Friday, ex-girlfriend Samantha Taylor told the court how a seething Pistorius had fired his pistol out of a car's open sun-roof after a heated argument with a police officer in September 2012.

Taylor said she, Pistorius and a friend, Darren Fresco, had been pulled over by a policeman for speeding. When he saw Pistorius' pistol lying on the car seat, the officer picked it up and emptied its magazine onto the floor of the car, prompting an outburst from Pistorius, she said.

When they were allowed to go on their way, Pistorius and Fresco started to joke about shooting out a traffic light, known in South Africa as a robot, Taylor said.

"Oscar was very angry," said Taylor, who was sitting in the back seat at the time of the incident. "Thereafter they were joking around and saying they wanted to shoot a robot."

"Two minutes after, I saw Oscar take his gun and shoot out of the car roof. A very loud sound. They both laughed," she said.

Taylor's testimony comes two days after the court heard how Pistorius accidentally fired a pistol under the table in a packed Johannesburg restaurant - right next to a child - and then asked his friend Fresco to take the blame.

PISTORIUS WOKE GIRLFRIEND

Taylor, who broke up with Pistorius when he started dating Steenkamp in late 2012, also described two other incidents in which Pistorius drew his gun.

The first was when he jumped out of his car at the gateway of his Pretoria housing complex and put his gun to the window of a black BMW that appeared to have been following him.

The other was when he woke up in the middle of the night after hearing a bang in the bathroom.

"Something hit the bathroom window and Oscar woke me up and asked me if I had heard it," Taylor said, noting that the noise had probably been generated by a passing storm. "He got up with his gun and walked out of the room."

Taylor, who broke into sobs twice during her testimony, also said there had been "one or two" other occasions when Pistorius woke her after hearing noises during the night.

The testimony contrasts with a Pistorius bail hearing affidavit in which he said he did not check whether Steenkamp was still in the bed before going into the bathroom to confront the supposed intruder on the night he shot her.

Pistorius had his lower legs amputated as a baby but went on to achieve international fame as the "fastest man on no legs", running on carbon-fiber prosthetic limbs.

Dubbed the "Blade Runner" for his stunning Paralympic performances, he ascended to the pantheon of track greats at the 2012 London Olympics when he reached the 400 meters semi-final competing against able-bodied athletes.

With good looks and an easy smile, he was a sponsors' dream, but since Steenkamp's killing the accounts of his behavior have revealed a dark side to his carefully groomed media persona.